JPH04150125A - High frequency reception circuit - Google Patents

Abstract

PURPOSE:To eliminate the need for a high frequency reference signal by converting a high frequency signal into a low frequency signal while holding the phase information of the high frequency signal as it is, transmitting the phase information as two digital signals intersecting orthogonally with each other, converting amplitude information into a digital signal and transmitting the signal, as well. CONSTITUTION:A 1st distribution output distributed into two by a reception signal distribution means 1 is frequency-divided at a prescribed division ratio facilitating the digital transmission and the result is decomposed into two signal components intersecting orthogonally with each other having a phase difference of 90 deg., they are digitized respectively and the phase information is represented by the two signal components and outputted by a phase information output means 3. Moreover, an amplitude information output means 8 is provided, which applies amplitude detection to the 2nd distribution output distributed into two by the reception signal distribution means 1 to output the result as amplitude information. Thus, a circuit distributing a high frequency reference signal to all reception circuits with high accuracy is not required.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a high frequency receiving circuit, and in particular to a high frequency receiving circuit that separates the amplitude and phase information of a high frequency received signal captured by a radar, converts it into a digital signal, and outputs it. Regarding circuits.

[Conventional technology]

Conventionally, this type of high-frequency receiving circuit, as shown in an example in FIG. Two phase detectors 11a and llb are used to compare the phases of the two 90-degree phase difference signals distributed by the power divider 10 with a reference signal, and a phase detector 1
1a.

11b, two video amplifiers 9a and 9b for amplifying each phase-detected video signal, and two sample holds 6a for converting these two video signals into digital signals. ,6
b and two A/D converters 7a and 7h,
The receiving circuit divides the received signal into two orthogonal signal components and outputs and transmits the split signals.

[Problem to be solved by the invention]

The conventional high-frequency receiving circuit described above requires two reference signals of the same amplitude and phase, so it is necessary to provide a terminal to receive the high-frequency reference signals, and it is necessary to maintain the amplitude and phase of the reference signals with high precision. Since this method must be divided into two high-frequency signals and transmitted to a phase detector, it has the drawback of requiring highly accurate circuit manufacturing and adjustment.

In particular, active phased array antennas that use thousands to tens of thousands of receiving circuits of this type require a circuit that accurately distributes high-frequency reference signals to all receiving circuits, making the reference signal transmission system extremely difficult. complex, expensive,
Moreover, it has the disadvantage of being large and causing an increase in weight.

[Means to solve the problem]

The circuit of the present invention is a high-frequency receiving circuit that receives a high-frequency received signal, separates its amplitude information and phase information, converts it into a digital signal, and outputs it, and includes a received signal distribution means that divides the inputted received signal into two. With this received signal distribution means, 2
The first distributed output is frequency-divided by a predetermined reduction ratio that facilitates digital transmission, and then decomposed into two orthogonal signal components with a 90 degree phase difference, each of which is digitized. A phase information output means for outputting phase information represented by a signal component, and an amplitude information output means for amplitude detecting a second distributed output divided into two by the received signal distribution means and outputting it as amplitude information. configured.

Further, in the circuit of the present invention, the phase information output by the phase information output means is expressed as tan-"B/A of the amplitudes A and B of the two orthogonal signal components having a 90 degree phase difference. The present invention has a configuration that provides the amplitudes A and B that determine the phase.

Furthermore, the circuit of the present invention has a configuration in which the high-frequency received signal is a received signal captured by a radar.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of a first embodiment of the present invention. The first embodiment shows the basic configuration of the present invention, in which a low noise amplifier 1 constitutes a received signal distribution means that divides the received signal into two.
, power divider 2, limiter amplifier 3 constituting phase information output means, frequency divider 4, phase difference power divider 5, sample and hold 6a, 6b=A/D converters 7a, 7b, constituting amplitude information output means It comprises an amplitude detector 8, a video amplifier 9, a sample hold 6c, and an A/D converter 7c.

Next, the operation of the first embodiment will be explained.

The received high frequency signal is amplified by a low noise amplifier 1 to improve reception sensitivity, and is divided into two by a power divider 2. The first distributed output is amplified by the limiter amplifier 3 to a constant level regardless of the input level, and is down-done by the frequency divider 4 to a frequency that facilitates digital transmission. Thereafter, the phase difference power divider 5 divides into two orthogonal signals, and the amplitude of each signal is sent to the sample holds 6a, 6b and the A/D converter 7a.

7b converts it into a digital signal. If the amplitudes of these two signals are A and B, respectively, the phase of the received signal is expressed as tan-1B/A, and these two digital signals are sent out to the transmission path as data that provides phase information of the received signal. Ru.

On the other hand, the second distribution output from the power amplification divider 2 is supplied to the amplitude detector 8. After this second distributed output is envelope-detected by the amplitude detector 5, it can be converted into a digital signal with high precision, and is amplified by the video amplifier 9 to a signal level, and converted into a digital signal by the sample-hold 6C and the A/D converter 7C. converted. This digital signal is sent to the transmission path as providing amplitude information of the received signal.

FIG. 2 is a block diagram of a second embodiment of the present invention. The second embodiment takes as an example the case where the present invention is applied to an active phased array antenna. A digital beam forming circuit 14 that weights and digitally calculates the phase information and amplitude information based on the phase information and amplitude information of the optical signal format obtained by processing, and forms a desired antenna beam; #m transmission/reception module 13a
This figure shows an active phased array antenna including an amplitude signal distribution circuit 15 that supplies an excitation signal for a transmission signal of ~13 m as a digital optical signal.

The transmitter/receiver module shown in FIG. 2, as shown in the #1 transmitter/receiver module 13a, includes an antenna element 16 for receiving or transmitting high-frequency electromagnetic waves, a transmitter/receiver switch 17 for switching between a transmitting signal and a receiving signal, and a limiter 18 that protects the receiving circuit, a low noise amplifier 10,
A Wilkinson type power divider 19 that functions as a power divider that divides the amplified received signal into two constitutes received signal distribution means.

Also, a limiter amplifier 3 that amplifies the first distribution output divided into two to a certain level, a 1/N prescaler 20 that is a frequency divider that decreases the frequency of the signal, and a 1/N prescaler 20 that reduces the frequency of the signal by 90 A 90-degree hybrid power divider 21 that has a function of distributing signals into two signals with a phase difference of 90 degrees, and sample holds 6a, 6b and A/D conversion for converting the distributed signals with a phase difference of 90 degrees into digital signals, respectively. The E/○ converters 22a and 22b that convert the power outputs of the A/D converters 7a and 7b into optical signals constitute phase information output means.

Furthermore, for the second distributed output, an amplitude detector 8 detects the signal, and a video amplifier 9 amplifies the detected video signal to a level that can accurately convert it into a digital signal.
, a sample hold 6c and an A/D converter 7c for converting the amplified video signal into a digital signal, and an E10 converter 22c for converting the digital signal output from the A/D converter 7C into an optical signal. Configure information output means.

The #l transmitting/receiving module 13a further includes an O/E converter 23 that converts the digital optical signal for transmission sent by optical transmission from the excitation signal distribution circuit 15 into an electrical signal, and an A multiplier 24 that converts the signal into a high-frequency transmission signal for transmission, and a phase shifter that controls the phase of the transmission signal so that a radiation beam is combined in an arbitrary direction when the transmission signal is radiated into space from the antenna element. 25
and a power amplifier 26 that amplifies the transmitted signal to a level that provides the desired radar coverage.

The high frequency signals received by the antenna elements 16 of the m transmitting/receiving modules 13a to 13m #1 to #m are sent to the limiter 18 through the transmitting/receiving switch 17, and are amplified to low noise by the low noise amplifier 1, and are amplified by the Wilkinson type. Power divider 19
The signal is divided into two at the first and second distribution outputs.

The first distributed output is limited and amplified by a limiter amplifier 3, then reduced in frequency by a 1/N prescaler 20 to suit digital transmission, and further has a phase difference of 90 degrees from each other by a 90 degree hybrid power divider 21. After being divided into two orthogonal signals, they are digitized by sample holds 6a, 6b and A/D converters 7a, 7b. In this embodiment, this digital electrical signal is then converted into a digital optical signal by the E10 converters 22a, 22b and supplied to the digital beam forming circuit 14.
The conversion can be carried out as desired, including the E/○ converter 22c, which will be described later, as well as the O/E converter 23, and it is of course possible to use the electric signal as it is.

Now, the second distributed output is amplitude-detected by an amplitude detector 8, then amplified by a video amplifier 96, and converted into digital amplitude information by a sample hold 6C and an A/D converter 7C, and then converted to digital amplitude information by an E10 converter 22C. is supplied to the digital beam forming circuit 14 as an optical signal.

The 0/E converter 23 receives an excitation signal in the form of an optical signal from the excitation signal distribution circuit 15, converts it into an electrical signal, and supplies it to the multiplier 24. The multiplier 24 multiplies this frequency to the transmission frequency to produce a transmission signal, and this transmission signal is given a phase necessary for beam formation of the transmission signal by a phase shifter 25, and then sent from a power amplifier 26 to a transmission/reception switch 17 and an antenna. Element 16
radiated by. A reflected signal of this radiated signal from the target is captured by the antenna element 16 and becomes the above-mentioned high frequency received signal.

In this way, phase information and amplitude information of a received signal can be easily and reliably obtained with a simple configuration and without using a reference signal.

〔Effect of the invention〕

As explained above, the present invention converts a high frequency signal into a low frequency signal while retaining phase information, transmits the phase information as a digital signal of two orthogonal components, and also converts amplitude information into a digital signal and transmits it. By making this possible, there is no need for a high-frequency reference signal at all, and by performing distribution into two orthogonal components at a lower frequency, there is no need to manufacture or adjust high-precision circuits. There is. In addition, by using it in an active phased array antenna, all digital signals can be transmitted without the need for a complex and high-precision high-frequency power divider, resulting in lower cost, smaller size, and lighter weight. There is.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment of the present invention, and FIG. 3 is a block diagram showing an example of a conventional high frequency receiving circuit. 1...Low noise amplifier, 2...Power divider, 3...
Limiter amplifier, 4... Frequency divider, 5... Phase difference power divider, 6a to 6C... Sample hold, 7a to 7C
...A/D converter, 8...amplitude detector, 9a, 9b
...Video amplifier, 10...Phase difference power divider, 1
1a llb... 1 phase shifter, 12... Power divider, 13a to 13m... #1 to #m transmitting/receiving module, 14... Digital beam forming circuit, 15... Excitation signal distribution circuit, 16... antenna element, 17...
Transmission/reception switch, 18... Limiter, 19... Wilkinson type power divider, 20... 1/N prescaler,
21...90 degree hybrid power divider, 22a-2
2c...E/○ converter, 23...○/E converter, 2
4... Multiplier, 25... Phase shifter, 26... Power amplifier.

Claims (1)

[Claims] 1. A high-frequency receiving circuit that receives a high-frequency received signal, separates its amplitude information and phase information, converts it into a digital signal, and outputs it, the received signal dividing the input received signal into two. a distribution means, and a first distribution output divided into two by the received signal distribution means is divided by a predetermined reduction ratio to facilitate digital transmission, and two signal components are orthogonal with a phase difference of 90 degrees from each other; phase information output means for decomposing into two signal components, digitizing each, and outputting phase information represented by these two signal components; and amplitude detection for the second distributed output divided into two by the received signal distribution means to generate amplitude information. and amplitude information output means for outputting amplitude information. 2. The phase information output by the phase information output means determines the phase expressed as tan^-^1B/A of the amplitudes A and B of the two orthogonal signal components having a 90 degree phase difference. 2. The high frequency receiving circuit according to claim 1, wherein the high frequency receiving circuit provides the amplitudes A and B. 3. The high frequency receiving circuit according to claim 1, wherein the high frequency received signal is a received signal captured by a radar.